Why tree lopping is not a viable solution for trees that have grown too large

Trees that have grown too large or too tall for the site they are on can present a hazard, and it is this fear that sometimes drives property owners to lop the tree. The term ‘lopping’ is used rather loosely to mean anything from thinning or pruning to compete for removal. The practice of lopping is the wholesale cutting of branches to stubs or lateral branches, removing between 50% to 100% of the tree’s foliage.

The most common reason for lopping or ‘topping’ is to reduce the size of the tree. Lopping a tree is seldom a final solution to height reduction as the practice seriously weakens and stresses the tree and it may die. Then, it will either need to be removed by a professional arborist or the stump will need to be removed.

Lopping is in fact prohibited by the Tree Protection Act of 2005 (ACT) and is classified as a tree damaging procedure.

Melbourne arborist and tree surgeon James O’Brien advises strongly against taking up this drastic measure without careful consideration, “Indiscriminate lopping can severely damage a tree, increasing susceptibility to insect and disease infestation and making it more hazardous in the long run. Removing the leaves can temporarily starve a tree, and large open pruning wounds expose the wood to attacks by pests and disease. The tree may then have insufficient stores of energy to chemically defend itself against these invasions.”

O’Brien says, “When cuts are made along a limb between lateral branches, this creates stubs with wounds that the tree may not be able to close and the exposed wood tissue begins to decay. Few trees are able to defend against multiple severe wounds caused by lopping.”

The correct location for a pruning cut is just beyond the branch collar at the point of attachment. “A tree is biologically equipped to close such a wound if it is healthy and the wound is not too large,” O’Brien said.

Severe pruning also triggers a survival response in the tree to put out new leaves as soon as possible. It will then activate latent buds and force the growth of multiple epicormic shoots below each cut.

Branches usually develop in a socket of overlapping wood tissue but epicormic shoots are anchored only in the outermost layers of the branches. These shoots grow up to 6m in a year for some species, and due to their shallow anchors, are prone to breaking especially during stormy conditions. Hence if the tree survives lopping, it will require pruning again within a few years.

Another consequence of removing most or all of the tree’s foliage is that the branches and trunk of the tree are no longer sheltered from the sun. Exposure to higher levels of light and heat can lead to sunburn, which in turn may result in further disease, bark splitting and death of the tree.

Professional arborists are taught not to practise incorrect lopping, and which procedures to employ instead to address a tree that has grown too large.

It’s therefore strongly advised to consult with a professional arborist before lopping a tree yourself. Alternative options such as pruning, removal of the tree or even relocation may be viable.

OB Trees are experts in the field of tree care and have almost a decade of hands-on experience in all aspects, specialising in pruning, tree removal and maintenance and vegetation management. Their team of trained arborists are able to provide the best advice for your particular needs, followed up with the most appropriate solutions at a competitive price.

The information contained in this article is based on the authors’ opinion only and is of a general nature which is not indicative of future results or events and does not consider your personal situation or particular needs. Professional advice should always be sought relevant to your circumstances.